Diffusion - Diffusion Moleclular diffusion follows Ficks...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
Diffusion Moleclular diffusion follows Fick’s first law: δ δ δ δ m t D C x dydz i =− or JD C x m t dydz ii  = δ δ δ δ m = weight of dissolved material t = time c = concentration x = direction of flow dy/dz= area of flow D i = diffusivity - grams of solute diffusing through 1.0 cm 2 /hr for 1 gm/cc conc. gradient over 1 cm Can solve by Fourier series as a partial deg. () CC e e e ts s dd d i + + + −− 0 811 1 9 1 25 0 92 5 .. . . C S = saturation concentration d i = coefficient of diffusion d Dt x i i = π 2 2 4 t = contact time If system is quiescent - diffusion controls mass transport D i = 0.5 x 10 -5 M 5 x 10 -5 in our water quality area
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
D i decreases with molecular weight and varies with Van Hoff - Arrhenius relationship () dD dT E RT i ln = 2 T = temperature (Kelvin) R = gas constant E = activation energy D i also varies with the square root of density and temperature [] De t ic 8 7 10 0 0159 20 2 ..
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 01/14/2012 for the course ENV 6015 taught by Professor Taylor during the Fall '11 term at University of Central Florida.

Page1 / 4

Diffusion - Diffusion Moleclular diffusion follows Ficks...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online